Nonreciprocal thermal photonics in magnetic topological materials from a first-principles toolbox

Nonreciprocal thermal photonics enables directional control of heat transfer and radiative energy conversion through broken reciprocity in material or structural response. In this work, we reveal topology-enhanced nonreciprocal thermal emission in magnetic topological materials using ab initio calculations, demonstrating that intrinsic topological effects can induce strong nonreciprocity even without an external magnetic field. By developing a first-principle toolbox, we computed nonreciprocal thermal radiation through ab initio calculation of optical dielectric tensor and electromagnetic modeling. We further predict a series of real materials exhibiting pronounced nonreciprocal effects in the mid-infrared range due to their topological band structures. Our work establishes a quantitative framework connecting ab initio electronic structure to nonreciprocal photonic phenomena, opening avenues for discovering new materials and developing novel directional thermal devices.